Polyester Toner Resin Low-Temperature Fixing Anti-Blocking
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Solution Overview
Problem
Conventional polyester resins for toners fail to adequately meet the demands for low temperature fixing, anti-blocking, and anti-offset properties in modern high-speed and energy-efficient copying machines and laser beam printers, as they tend to agglomerate and cause offset issues due to reduced glass transition temperature.
Innovation Solution
A polyester resin for toners is developed, comprising an acid component with aromatic dicarboxylic acid and disproportionated rosin, and an alcohol component with tri- or more-valent polyhydric alcohol, with specific molar ratios to achieve improved low temperature fixing, anti-blocking, and anti-offset properties, characterized by a softening temperature of 105-150°C and glass transition temperature of 45-80°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the softening temperature (Tm) of the resin for toner is reduced to improve low temperature fixing property, then the fixing temperature can be decreased, but the glass transition temperature (Tg) will fall simultaneously causing toner blocking and offset phenomenon
Solution Approach 1:
The invention changes the chemical composition parameters of the polyester resin by incorporating specific components (rosin, aromatic dicarboxylic acid, tri- or more-valent polyhydric alcohol) in controlled ratios. This modifies the resin's thermal parameters (Tm and Tg) to achieve independent control - lowering Tm for low-temperature fixing while maintaining Tg above 70°C to prevent blocking and offset
Solution Approach 2:
The invention creates a composite polyester resin system combining multiple acid components (rosin, aromatic dicarboxylic acid) and alcohol components (tri- or more-valent polyhydric alcohol) with specific molar ratios. This composite structure enables synergistic effects where the combination of components achieves both low Tm and high Tg, resolving the contradiction between low-temperature fixing and anti-blocking properties
2Reliability
If conventional polyester resin is used to maintain anti-blocking property, then Tg remains stable, but low temperature fixing property is insufficient for modern high-speed and energy-efficient copying machines
Solution Approach 1:
The invention modifies the resin composition to achieve a specific parameter combination: Tm ≤ 150°C and Tg ≥ 70°C. By controlling the molar ratios of acid to alcohol components and using specific component types, the resin achieves both low fixing temperature capability and high anti-blocking performance, meeting modern copying machine requirements
3Productivity
If the fixing time is shortened and heating temperature is decreased for energy saving, then productivity and energy efficiency improve, but conventional polyester resin cannot achieve adequate fixing property
Solution Approach 1:
The resin's thermal parameters are optimized to enable rapid heating and cooling cycles. The low Tm (≤150°C) allows quick melting and fixing, while the high Tg (≥70°C) ensures rapid solidification after fixing, enabling short fixing times for high-speed copying machines without sacrificing image quality
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a toner with enhanced low temperature fixing, anti-blocking, and anti-offset properties, ensuring improved storage stability, reduced agglomeration, and effective image formation, even at lower fixing temperatures, thus enabling energy savings and smaller apparatus sizes.
Implementation Method 1
a polyester resin for toner comprising an acid component and an alcohol component, characterized in that the acid component comprises (1) an aromatic dicarboxylic acid and (2) a disproportionated rosin, and the alcohol component comprises (3) a tri- or more-valent polyhydric alcohol
Data Source
AI summary
A toner for developing an electrostatic charge image which contains a polyester resin as a binder resin is provided. The toner has excellent toner properties including low temperature fixing properties, anti-blocking property and anti-offset property, etc. Also a polyester resin for a toner is provided, which is used in the above-mentioned toner. As the binder resin for toner, a polyester resin comprising (1) an aromatic dicarboxylic acid and (2) a disproportionated rosin as an acid component, and (3) a tri- or more-valent polyhydric alcohol as an alcohol component is used, wherein the molar ratio (3)/(1) of the alcohol component (3) and the acid component (1) is from 1.05 to 1.65 and the molar ratio (2)/(1) of the acid components (2) and (1) is from 0.40 to 2.60.